diff --git a/src/arm/cpu/arm/psr_transfer.zig b/src/arm/cpu/arm/psr_transfer.zig
index 3dbf962..0f1ae47 100644
--- a/src/arm/cpu/arm/psr_transfer.zig
+++ b/src/arm/cpu/arm/psr_transfer.zig
@@ -49,34 +49,38 @@ pub fn control(comptime InstrFn: type, comptime I: bool, comptime op: u6) InstrF
 
                     cpu.pipe.reload(cpu);
                 },
-                0b00_0101, 0b01_0101 => { // QADD / QSUB
+                0b00_0101, 0b01_0101, 0b10_0101, 0b11_0101 => { // QADD / QDADD / QSUB / QDSUB
                     const U = op >> 4 & 1 == 1;
+                    const D = op >> 5 & 1 == 1;
 
                     const rm = opcode & 0xF;
                     const rd = opcode >> 12 & 0xF;
                     const rn = opcode >> 16 & 0xF;
 
                     const left: i32 = @bitCast(cpu.r[rm]);
-                    const right: i32 = @bitCast(cpu.r[rn]);
+                    const right: i32 = blk: {
+                        if (!D) break :blk @bitCast(cpu.r[rn]);
 
-                    cpu.r[rd] = @bitCast(if (U) left -| right else left +| right);
+                        const ret = @mulWithOverflow(@as(i32, @bitCast(cpu.r[rn])), 2);
+                        var product: i32 = ret[0];
 
-                    if (cpu.r[rd] == 0x8000_0000 or cpu.r[rd] == 0x7FFF_FFFF) cpu.cpsr.q.set();
-                },
-                0b10_0101, 0b11_0101 => { // QDADD / QDSUB
-                    const U = op >> 4 & 1 == 1;
+                        if (ret[1] == 0b1) {
+                            product = if (product < 0) std.math.maxInt(i32) else std.math.minInt(i32);
+                            cpu.cpsr.q.set();
+                        }
 
-                    const rm = opcode & 0xF;
-                    const rd = opcode >> 8 & 0xF;
-                    const rn = opcode >> 16 & 0xF;
+                        break :blk product;
+                    };
 
-                    const product = @as(i32, @bitCast(cpu.r[rn])) *| 2;
-                    if (product == 0x7FFF_FFFF) cpu.cpsr.q.set();
+                    const ret = if (U) @subWithOverflow(left, right) else @addWithOverflow(left, right);
+                    var result: i32 = ret[0];
 
-                    const left: i32 = @bitCast(cpu.r[rm]);
+                    if (ret[1] == 0b1) {
+                        result = if (result < 0) std.math.maxInt(i32) else std.math.minInt(i32);
+                        cpu.cpsr.q.set();
+                    }
 
-                    cpu.r[rd] = @bitCast(if (U) left -| product else left +| product);
-                    if (cpu.r[rd] == 0x8000_0000 or cpu.r[rd] == 0x7FFF_FFFF) cpu.cpsr.q.set();
+                    cpu.r[rd] = @bitCast(result);
                 },
                 0b01_0111 => cpu.panic("TODO: handle BKPT", .{}),
                 0b00_1000, 0b00_1010, 0b00_1100, 0b00_1110 => { // SMLA<x><y>